Question

I have an example here:

int runcmd(char *cmd)
{
  char* argv[MAX_ARGS];
  pid_t child_pid;
  int child_status;

  parsecmd(cmd,argv);
  child_pid = fork();
  if(child_pid == 0) {
    /* This is done by the child process. */

    execvp(argv[0], argv);

    /* If execvp returns, it must have failed. */

    printf("Unknown command\n");
    exit(0);
  }
  else {
     /* This is run by the parent.  Wait for the child
        to terminate. */

     do {
       pid_t tpid = wait(&child_status);
       if(tpid != child_pid) process_terminated(tpid);
     } while(tpid != child_pid);

     return child_status;
  }
}

This one is a classic example of fork()
After fork(), the control goes to child process.
How can I keep in parent process, do stuffs. Instead of jumping to child immediately?

Thank you

Answer 1

The child will always be the child. The parent will always be the parent. fork() creates a new process, and each runs separately. If you want to do something in the parent then do it in the parent.